CVE-2021-34816: An Argument Injection issue in the plugin management of Etherpad 1.8.13 allows privileged users to execute arb

This month

HIGH 7.2DOWNGRADE

CVE-2021-34816 is a high-severity flaw (CVSS 7.2) affecting etherpad. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An Argument Injection issue in the plugin management of Etherpad 1.8.13 allows privileged users to execute arbitrary code on the server by installing plugins from an attacker-controlled source.

Why this priority

High severity
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.2 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	2.2% (top 17%)
CISA exploited list	No
Weakness	CWE-88
Published	2021-07-21
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: etherpad

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-07-21 18:15 UTCPublished CVE record published
2026-06-17 03:56 UTCUpdated Record last modified

etherpad etherpad DOWNGRADE

Affected: 1.8.13

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8.13

1. Check installed version

apt-cache policy etherpad || rpm -q etherpad || etherpad --version

2. No fixed release: DOWNGRADE to a release before 1.8.13 (Debian / Ubuntu)

apt-cache madison etherpad sudo apt install etherpad=<VERSION_BEFORE_1.8.13> sudo apt-mark hold etherpad

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list etherpad sudo dnf downgrade etherpad-<VERSION_BEFORE_1.8.13> sudo dnf versionlock add etherpad

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-34816?

etherpad: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-34816 being exploited?

CVE-2021-34816 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-34816 affect?

CVE-2021-34816 affects etherpad. Severity is high (CVSS 7.2). An Argument Injection issue in the plugin management of Etherpad 1.8.13 allows privileged users to execute arbitrary code on the server by installing plugins from an attacker-controlled source.

How urgent is CVE-2021-34816?

Priority 51/100. High severity; Public exploit reference

Related CVEs

CVE-2021-43802 CRITICAL 9.9 UPGRADE Etherpad is a real-time collaborative editor
CVE-2021-34817 MEDIUM 6.1 DOWNGRADE A Cross-Site Scripting (XSS) issue in the chat component of Etherpad 1.8.13 allows remote attackers to inject
CVE-2020-22785 HIGH 7.5 UPGRADE Etherpad < 1.8.3 is affected by a missing lock check which could cause a denial of service
CVE-2020-22783 MEDIUM 6.5 UPGRADE Etherpad <1.8.3 stored passwords used by users insecurely in the database and in log files
CVE-2020-22782 HIGH 7.5 UPGRADE Etherpad < 1.8.3 is affected by a denial of service in the import functionality

References

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